The present invention relates generally to audio communication and in particular the present invention relates to capturing audio data transmissions.
In many digital communication systems, audio captured at a remote location is delivered to a local location in either a continuous stream of data, or in bursts of data packets. When a continuous stream is delivered, it contains all audio captured at the remote location. When bursts of data packets are delivered, the packets typically contain only speech or music deemed important by the remote endpoint. Thus, the packets containing silence are typically not delivered. These audio packets can arrive at the local location at unpredictable intervals, or may even be dropped, due to unreliable network behavior or audio system behavior caused by heavy loading. These unpredictable delivery patterns make it extremely difficult to design Half-Duplex Open Audio functionality into such systems.
Traditional half-duplex hands-free audio systems assume that a continuous stream of remote audio is delivered, and that the contents of remote audio can be analyzed using a voice activity detector (VAD) to make meaningful speech/noise classifications on the received audio data. Because remote locations adhering to new protocols attempt to conserve network bandwidth by dropping rather than transmitting unnecessary audio packets, the assumption of continuous data does not hold true on today""s digital systems. Thus, the local half-duplex communication algorithms do not get a chance to analyze the content of all the audio captured at the remote location. Half-duplex communication algorithms operating under these conditions either rely on remote speech/noise classifications when determining whether the remote audio should be played at the local site or, play all audio received, under the assumption that all packets received from the remote site contain meaningful audio.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a communication system which allows half-duplex communication in systems receiving either continuous data or packet-based data.
In one embodiment, a communication receiving device comprising a density measurement device is coupled to receive an input audio signal and provide an output indicating if the received input audio signal contains speech signals based upon a density of the input audio signal. A voice activity detector is coupled to receive the input audio signal and provide an output indicating if the received input audio signal contains speech signals based upon energy levels of the input audio signal. A parser device is coupled to receive the input audio signal and provide an output indicating if the received input audio signal contains speech signals based upon data provided with the input audio signal. A classifier device is coupled to the density measurement device, voice activity detector, and parser device for classifying the received input audio signal.
In another embodiment, a half duplex switching device comprising an input connection for receiving an input audio signal, and classification module are coupled to the input connection. The classification module provides an output which indicates a classification of the input signal based upon a density of the input signal, an energy level of the input signal, and classification data provided with the input audio signal. A switching device is coupled to the classification module. The switching device determines if the received input audio signal contains speech signals based upon the output of the classification module.